This invention involves an apparatus to clean a carrier, such as soil, contaminated with biodegradable chemical compounds, such as halogenated organic chemicals.
One of the most vexing problems associated with hazardous waste sites is the difficulty in the cleaning of the soils which has been subjected to a spill or even long term usage involving chlorinated hydrocarbons. The hazardous nature of chlorinated hydrocarbons and hydrocarbon derivatives is well documented. The chlorinated hydrocarbons extensively used in dry cleaning establishments and as minor but persistent components in petroleum products continue to cause great problems. While the chlorinated aliphatic hydrocarbon poses difficulty, the chlorinated aromatic hydrocarbons and in particular the fully halogenated hydrocarbon derivatives pose even greater problems.
Bioremediation using microorganisms has offered the most effective method of cleaning up hazardous waste sites. The use of microorganisms which are designed to break down certain chemical compounds and more importantly to selectively secrete enzymes to break down the more completely chlorinated hydrocarbons is well documented. These compounds, referred to herein as biodegradable chemical compounds, include not only partially halogenated but also fully halogenated carbon based compounds. These compounds are classified as "BOD" (biological oxidizable demand) which require additional oxygen during bioremediation with the treatment being enhanced by micronutrients, trace metals, organic acids, alcohols and other compounds. The more difficult compounds, such as PCB's, are classified "COD" (chemical oxidizable demand) requiring prior chemical reaction before digestion is effective by the microorganisms.
In addition to waste spills contaminating the ground, there is the need for bioremediation of a waste product stream from a chemical plant. In order to avoid having to pay a waste treatment company to break down these hazardous chemicals, there is a need for a small waste treatment unit which can be housed at the site where the waste stream of hazardous chemicals is created. This in-house bioremediation waste treatment unit need not involve the use of soil as a carrier, but may utilize any suitable carrier including clean sand or the like.
One of the problems associated with bioremediation techniques is that the vapor by-product of the completed reaction is carbon dioxide which is ultimately vented to the atmosphere. In order to avoid small quantities of organic compounds being vaporized and entrained with the issuing gases, special filters, such as activated carbon, scrubbers, and like equipment have been required to make sure that the atmosphere is not polluted as a result of the waste disposal reaction. The use of filters and scrubbers severely increase the cost and reduce the efficiency of the system and are generally directed to extremely small quantities of the noxious or possibly toxic vapors.
A number of bioremediation systems have been provided particularly including U.S. Pat. No. 4,992,174 to Jason A. Caplan et al, U.S. Pat. No. 4,850,745 to gary R. Hater et al, U.S. Pat. No. 4,401,569 to Vidyut Jhaveri et al, U.S. Pat. No. 4,849,360 to Robert D. Norris et al, U.S. Pat. No. 4,765,902 to Douglas L. Ely et al, and U.S. Pat. No. 4,945,988 to Frederick C. Payne et al, all incorporated herein by reference to describe the standard bioremediation organisms, techniques, and apparatus.
None of these systems and methods satisfy the problem of gases issuing from the bioremediation system nor attain the objects described hereinbelow.